Low Temperature X-ray Microanalysis Research Articles

Correction to: Low-Temperature X-ray Microanalysis Sheds New Light on Mineral Nutrition Aspects of Insect Leaf Galling.

Correction to: Low-Temperature X-ray Microanalysis Sheds New Light on Mineral Nutrition Aspects of Insect Leaf Galling.

Low-Temperature X-ray Microanalysis Sheds New Light on Mineral Nutrition Aspects of Insect Leaf Galling.

Manipulation of host plant physiology by leaf-galling insects is a multifaceted process. Among fundamental knowledge gaps surrounding this scientifically intriguing phenomenon is the appropriation of plant mineral nutrients and moisture for galling advantage. Small, soluble mineral ions and watery cell contents in dense gall tissues risk disruption during routine sample preparations. In this study, an X-ray microanalysis was applied to investigate gall mineral nutrition. Morphologically diverse leaf galls were sampled from three Australian rainforest tree species. Using cryo-analytical scanning electron microscopy, real-time X-ray analytical maps of cellular mineral nutrients and water were integrated with anatomical images of gall and leaf cross-sectional surfaces. A comparison of host-leaf and gall anatomies bore direct evidence of drastic changes to leaf cells through the galling process. Distinct "wet" and "dry" regions within galls were anatomically and/or chemically differentiated, suggesting specific functionality. "Wet" regions comprising hydrated cells including soft gall-cavity linings where larvae are known to feed contained soluble plant mineral nutrients, while C-rich "dry" tissues largely devoid of mineral nutrients likely contribute structural support. Mapping immobile nutrients such as Mn may provide a means of "matching" specific gall cell types to those in ungalled host-leaf tissues. The findings here provided otherwise inaccessible insights into leaf-gall mineral nutrition.

Low temperature X-ray microanalysis of calcium in a scleractinian coral: evidence of active transport mechanisms.

Element concentrations were measured by X-ray microanalysis in seawater (SW) compartments and mucocytes in bulk, frozen-hydrated preparations of the scleractinian coral Galaxea fascicularis. Quantitative X-ray microanalysis of polyps sampled in the daytime revealed that concentrations of the elements Na, S, K and Ca were all significantly higher in a thin (10-20 micro m) external SW layer adjacent to the oral ectoderm (P<0.05, <0.05, <0.0001 and <0.01, respectively) than in standard SW. In polyps sampled during night-time, concentrations of Ca and S in this external SW layer were significantly reduced (P<0.05). Ca concentration in the coelenteron and extrathecal coelenteron was significantly higher (P<0.001) than in the external SW layer, regardless of time of sampling, suggesting that Ca(2+) transport across the oral epithelium occurs via an active, transcellular route. X-ray microanalyses of mucocytes revealed that the concentration of S was high and did not vary between epithelial layers, while that of Ca increased in an inward gradient toward the skeleton. We suggest that throughout the day, secreted mucus behaves as a Donnan matrix at the oral ectoderm-SW interface, facilitating intracellular Ca(2+) uptake. The accumulation within internal SW compartments of high concentrations of Ca relative to standard SW levels, however, appears to be independent of mucus secretion and is likely to be a consequence of active transport processes.

The distribution of calcium and magnesium in developing tobacco leaves as measured by low-temperature X-ray microanalysis

The processes of leaf maturation and senescence are linked closely to the redirection of ions and organic nutrients between leaves and other part of the plant. It is known from work on whole leaves, that Ca2+ and Mg2+ play an important role in leaf development, although no studies have been made of changes at the cell and tissue level. This present study follows the cellular changes in Ca2+ and Mg2+ in the epidermal and photosynthetic tissues by X-ray microanalysis of frozen hydrated leaves.Full details of sample preparation, instrumentation, and the basis of the quantitative procedures have been reported elsewhere. Flat, frozen hydrated fracture faces of upper and lower epidermis; palisade and spongy mesophyll cells were analysed for Ca2+ and Mg2+. Data was collected from each of the four cell types in 20 different leaves at each of the following five stages of growth. Juvenile (10 weeks from seed); Mature (13 weeks), Ripe (16 weeks), Senescent (19 weeks) and Old (21 weeks). Cells containing obvious calcium oxalate crystals were avoided.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

The Uptake and Distribution of Potassium in Roots of Duckweed (Lemna Minor L) As Measured using Low Temperature X-Ray Microanalysis

Lemna minor L. plants were grown in a 14 H light and 10 H dark regime at 298 K in a medium containing 2 mM [K+]. Roots, 20 mm long and photosynthetically active, were removed and prepared for low temperature microscopy using methods described elsewhere. Fracture faces were made using the AMRAY Biochamber and the analysis carried out using an AMRAY 1000A SEM fitted with an LaB6 gun and a Kevex Si (Li) x-ray detector at 15-17 kV and a beam current of 1-2 nA. A reduced raster (1.0 μm2) was placed at the centre of the cell being analysed, care being taken to avoid any contact with the cell walls. Samples were maintained at 100-110 K throughout analysis and an LN2 cooled anti-contamination device was inserted close to the specimen. The spectra were analysed using the peak/background (P/B) ratio technique following use of background subtraction and peak de-convolution routines. Between eight and twelve fracture faces were analysed for each of the ten sites along the length of the root and the data pooled and presented in Table I.

Quantitative low temperature X-ray microanalysis of biological specimens

Quantitative low temperature X-ray microanalysis of biological specimens

Low temperature X-ray microanalysis of ion and water transporting epithelia in insects

Low temperature X-ray microanalysis of ion and water transporting epithelia in insects

The use of polymeric cryoprotectants in low-temperature X-ray microanalysis of biological specimens

The use of polymeric cryoprotectants in low-temperature X-ray microanalysis of biological specimens